Japanese Patent Early-Publication 57-102756, assigned to the applicant of the present application, discloses a shot-blasting machine that includes an inclinable rotary drum for stirring work pieces to be cleaned, and a bucket loader for loading the work pieces into the rotary drum. In this prior-art machine, the bucket loader is lifted above and is then inclined toward a top opening of the rotary drum such that the work pieces within the bucket loader tumble into the rotary drum by their own weight.
In the prior-art shot-blasting machine, however, the bucket loader positioned above the top opening of the rotary drum must be significantly inclined to enable the work pieces therein to tumble by their own weight. At this time, the bucket loader should also be located at a level that is a great distance apart from the inner peripheral wall or the bottom wall (on which the tumbled work pieces land or collide with the bucket loader). Accordingly, the tumbled work pieces fall down at a relatively high rate and thus crash onto the inner peripheral wall or the bottom wall of the bucket loader, or crush other work pieces or work pieces located on the bottom wall. Therefore, problems wherein the work pieces show signs of brushing or damage and thus induce noisy hitting sounds have arisen.